Remove support for Object.observe

src/ic/ic.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/ic/ic.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/api-arguments.h"
 #include "src/arguments.h"
@@ skipping 1395 matching lines @@
         Object::SetProperty(object, name, value, language_mode()), Object);
     return result;
   }
 
   // If the object is undefined or null it's illegal to try to set any
   // properties on it; throw a TypeError in that case.
   if (object->IsUndefined() || object->IsNull()) {
     return TypeError(MessageTemplate::kNonObjectPropertyStore, object, name);
   }
 
-  // Observed objects are always modified through the runtime.
-  if (object->IsHeapObject() &&
-      Handle<HeapObject>::cast(object)->map()->is_observed()) {
-    Handle<Object> result;
-    ASSIGN_RETURN_ON_EXCEPTION(
-        isolate(), result,
-        Object::SetProperty(object, name, value, language_mode(), store_mode),
-        Object);
-    return result;
-  }
-
   LookupIterator it(object, name);
   if (FLAG_use_ic) UpdateCaches(&it, value, store_mode);
 
   MAYBE_RETURN_NULL(
       Object::SetProperty(&it, value, language_mode(), store_mode));
   return value;
 }
 
 Handle<Code> CallIC::initialize_stub_in_optimized_code(
     Isolate* isolate, int argc, ConvertReceiverMode mode,
@@ skipping 450 matching lines @@
         Object);
     if (!is_vector_set()) {
       ConfigureVectorState(MEGAMORPHIC, key);
       TRACE_GENERIC_IC(isolate(), "KeyedStoreIC",
                        "unhandled internalized string key");
       TRACE_IC("StoreIC", key);
     }
     return store_handle;
   }
 
-  bool use_ic =
-      FLAG_use_ic && !object->IsStringWrapper() &&
-      !object->IsAccessCheckNeeded() && !object->IsJSGlobalProxy() &&
-      !(object->IsJSObject() && JSObject::cast(*object)->map()->is_observed());
+  bool use_ic = FLAG_use_ic && !object->IsStringWrapper() &&
+                !object->IsAccessCheckNeeded() && !object->IsJSGlobalProxy();
   if (use_ic && !object->IsSmi()) {
     // Don't use ICs for maps of the objects in Array's prototype chain. We
     // expect to be able to trap element sets to objects with those maps in
     // the runtime to enable optimization of element hole access.
     Handle<HeapObject> heap_object = Handle<HeapObject>::cast(object);
     if (heap_object->map()->IsMapInArrayPrototypeChain()) {
       TRACE_GENERIC_IC(isolate(), "KeyedStoreIC", "map in array prototype");
       use_ic = false;
     }
   }
@@ skipping 846 matching lines @@
     KeyedLoadICNexus nexus(vector, vector_slot);
     KeyedLoadIC ic(IC::EXTRA_CALL_FRAME, isolate, &nexus);
     ic.UpdateState(receiver, key);
     ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, ic.Load(receiver, key));
   }
 
   return *result;
 }
 }  // namespace internal
 }  // namespace v8